Significant Accounting Policies, Noncontrolling Interest in Akcea (Details) - Akcea [Member] - shares shares in Millions	3 Months Ended
	Dec. 31, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2017
Noncontrolling Interest in Akcea Therapeutics, Inc. [Abstract]
Percentage ownership			76.00%	100.00%
Additional shares of Akcea stock received (in shares)	6.9	2.8
Minimum [Member]
Noncontrolling Interest in Akcea Therapeutics, Inc. [Abstract]
Percentage ownership			68.00%
Maximum [Member]
Noncontrolling Interest in Akcea Therapeutics, Inc. [Abstract]
Percentage ownership			77.00%